Regioselective Electrochemical Borylation of Oxygenated Allylic Electrophiles: Method Development and Synthetic...

Allylboronic esters are highly versatile intermediates in organic synthesis. In this work, we report a general and scalable strategy for the regioselective deoxygenative borylation of allylic alcohols, enals, enones, and acrylates, upgrading these abundant functional groups in feedstock chemicals and natural products into value-added borylated synthetic handles. This method achieves efficient C-O bond activation under mild electroreductive conditions, and the effective control of regioselectivity was made possible by optimizing the borylating agent and supporting electrolyte. The utility of this approach was further demonstrated in a series of telescoped synthetic sequences, enabling alcohol and carbonyl transposition, formal cross-coupling of alcohols and aldehydes, allylic amination, and vinylogous homologation. This electrosynthetic protocol offers a broadly applicable, modular route to complex allylboron compounds from simple and readily available starting materials, including terpenoid natural products.